Balanced davit.



A. A. SAWMAN.

BALANGED DAVIT.. APPLICATION FILED DB0. 5, 191s.

' ,Patented '14111128.1914

2 SHEETS- SHEET 1.

v' Fg I I l WML, @gw/VM A. A. SAWMAN.

BALANGBD DAVIT.

APPLICATION FILED DEQ. 5. 191s.

2 SHEETS-SHEET 2.

Patented Apr. 28, 1914.

] nue nto@ .STATES PTENT oFFIeE.

saw-MAN, 'or'BRooKLYn NEW Yoan.

BALANCE@ Devir.

1.0942150;iigg

Kings-and State of New York, have invented certain new and useful Improvements in.

Balanced Davits a specification. l:

This,lnventionrelates te improvements in balancedt davits forraising and lowering "of which the following is yItis. an .especial purpose of the invention to provide .davits and the operating mechanism thereof, so constructed and arranged that the Various forces and strains acting upon `the davitsshall be so proportioned and related` to each otherv that the ,davitshall be in v balance and remain securely in Whatever position it may be until the attendants opera-tev the mechanisms for shitting the davit` to `another position.

Other advantages of the invention are that' it provides' a simple, cheap and strong construction with'very few parts, which parts are easy of access .and assembling. In fact a davit installation consists of only two principal parts, z'. c. the davit per se and itsl frame.

Another advantage is that practically all the mechanism for raising and lowering the davit is mounted on the davit itself.v

A further advantage is that the crank or handle by which the davit operating mechanism is actuated is located in such a posi tion, at the side and well forward or' the davit, that the operator can watch the boat as he raises or lowers the boat; whereas with davits, as heretofore constructed, the operator is in such a position that lie cannot Watch the boat, and therefore is at a great disadvantage in controlling` the movements of the davit, as compared with a man who can watch the boat.

Other advantages willbe evident from th description hereinfter set i'orth, in connec i specification of Lettersratent.

Patented Apr. 28, 1914;

Application lied December 5, 1913. Serial No, 804,837.

zontal section on the brokenline H of Fig. l; Fig. 5 is a broken section and elevation of the bevel gear and worm screw on the line 5-5 of Fig. 2.

It being understood that two davits are ar 'anged in pairs, one davit for each end of a boat, and that the construction of the davits' and their operating mechanisms are similar to each other, each davit A being suitablyequipped with tackle and falls, is provided at a suitable point, relatively nearer its lower end, with trunnions a turning on an axle b in bearings c, secured to frame B. I prefer to form said trunnions a-a hollow, so as to 'turn on the said trans verse axle b which is carried by said bearings c. Said davit A, of any suitable materia-l, may either be straight as indicated in F1g.2, or curved as indicated in Fig. 3, and is preferably larger and heavier at itslower part thanv at its upper, to aid in securing the aforesaid balance. Said frames B preferably consist of two upright rectangular forgings suitably fastened to the deck of the ship, and spaced apart sulhciently to permit the lower end of said davit to work between them, and I prefer to form the foot block E of said davit A of such width as to lit with easy working t between said frames B.

A worm screw F is mounted on said davit `A parallel thereto, the lower end of said worin screw turning in a socket in the said block E, and the upper end thereof turnin in a socket in the bracket (l, which is firmly secured to said davit A. Said worm screw F is provided with a bevel gear Gr meshing with a bevel gear I-I fixed on a stud or axle, revolving` in a bracket I carried by said davit A, and heilig provided with a crank J for revolving said gear H. I prefer the construction shown in Fig. 5, wherein said bevel gear\G`fits on the square enlarged portion of the end pivot g ofvsaid worm screw F, and the axial stud 7i of said bevel gear G turns lin a hole in said' bracket d, being retained in position by a nut z', and washer as indicated in Fig. 5. Said worm screw F works through a nut K, which is pivot-ed between the upper ends of rocking arm If-L, which are in turn pivoted at their geo trames B-B, 3); said arms L-L being preferably bent inwardly and up- \\ardly about as indicated in Fig. 3. B this construction, said nut l can both oseillate on its own pivot and also swing about the pivots of said arms LL, so as to accommodate itseltl to any angle and position between the extreme limits of the mot-ion oi' said davit A. The position ofisaid pivots Z--Z is sach, that when said davit A is at its extreme upper or inboard position., that the line through the pivots of said nut K and said arms LL inelines upwardly and inwardly i'rom the longitudinal axis oi said worin screw l". Such angular' relation et' the said lines may he more concisely expressed by the phrase, the arms Lwli are inclined inwardly .troni said davit A.' When the said davits and the worin screw, the nut and the roei arms are arranged as hereinbe'ore described, then the davit will be balanced in whatever position it assumes, and will 'remain securely in that position until said worm screw is revolved to shift the Vdavit to another position. I prefer to provide the lower part A ot said davit with a longitudinal dove tail rib 0, on which tits a dove tail groove in the edge ot said nut l.

it will be evident from the it'oregoing description that| the invention operates in the following manner, one or more men being stationed at each davit to revolve said rranli J, and handle the tackles. It a boat is lo be li'iwered, then the cheeks (not shown) having been removed, the nien at the two davils turn the said cranks J and thereby ultimately revolve said worin screw' F by means olf Ythe worin gears G. H, in the direction ior moving said nut K downwardly. {iueh nio-lion. ot said nut K swings the lower ends ot said dav'its inboard, and the outer end thereof outboard, by reason ofthe aforesaid angular' pesilion of said arms L-L with respert. to said davits until said da vits )t attain tliei extreme outboard position, when the boat will be lowered by the men at the tackles. To raise the boat, the revolution of the worm screws will. be in the opposite direction from that for lowering it, and the davits will as hereinbe't'ore stated, be in balance through all their movement, so that they will remain securely with the boat hanging from them, in any position. A stop may be provided to properly limit the outboard motion of the davits.

Now having described my improvements, I Claim as my invention.

l. The combination with a swinging davit of a worm screw carried thereby, andV of means to revolve said screw, a nut engaging said screw, and pivoted arms' carrying said nut and arranged at an angle with said davit, whereby said davit is in balance in all its positions.

Q. The combination with a swinging davit oi' a worm screw Carried thereby, rotary gears operatively connected therewith and means to rotate said gears, a nut engaging said worm, and oscillating arms ,Carryingsaid nut and arranged at an angle'with said davit for the purpose hereinbet'oie described.

3. The eombination in a davit installation of a swinging davit, a frame on which said davit is pivoted, a worm screw mounted on said davit, bevel gears for revolving said screw and means to operate said gears, and an oscillating arm on which a nut engaging said worin is pivoted, said oscillating arm being at an inwardly and upwardly angle from said davit.

Signed at Brooklyn, in the county of Kings, vand State of New York, this L ith day of December, A. D. 1913.

lVitne-sses 711. A. HALL, CHARLES XV. feminin 

